Self-closing bag



Oct. 7, 1958 C. M. CLAY SELF-CLOSING BAG Filed Jan. 2'7, 1955 INVENTOR.

AZTORNEX United States Patent C 2,855,136 I SELF-CLOSING BAG Calvin Maurice Clay, Smithville, Miss., assignor to International Minerals & Chemical Corporation, a corporation of New York Application January 27, 1955, Serial No. 484,420

' 1 Claim. Cl. 229-425 This invention relates to closed bags. More particularly, it relates to bags which are filled by means of a spout or nozzle inserted through a valve which valve may be closed by pressure of the bag contents thereagainst when the filled bag is tipped.

Self-closing bags have been in commercial use for a number of years. These bags are inexpensive to fabricate and offer a simplified filling and handling operation. The chief drawback to bags such as have been made in accordance with the inventions disclosed in U. S. Patents 1,356,114 and 2,148,648 is that the bags continuously leak a small amount of material during all loading and transportation operations. The old style bags leaked material while being dropped, for example, on hand trucks and during movement on the trucks, as well as while being stacked in freight cars for delivery. These losses require that the bags be overfilled to compensate for losses, and this constitutes an uneconomical means of insuring that the customer receives the amount of product contracted for.

It is a primary object of this invention to overcome the shortcomings and disadvantages of self-closing bags heretofore in use.

It is another object of this invention to provide a selfclosing bag giving substantially no losses by leakage during handling and during stacking, transportation and storage.

These and other objects and advantages will be apparent to those skilled in the art from the following description.

Briefly, it has nowbeen discovered that the losses due to leakages through the filling spout can be substantially completely eliminated if the interned extension forming the filling spout is extended beyond a minimum length and the heretofore horizontal bottom of the spout opening is angled upwardly a minimum of about 3 degrees from the horizontal position.

When formed as heretofore described, the spout for self-closing bags has been determined to have an opti mum tongue length in the range between about 3 inches and about 6 inches, preferably between about 5 inches and about 6 inches for bags such as will hold 50 to 100 pounds of material.

The angle of upward tip from the horizontal of the tongue is in general greater the shorter the tongue length. With tongue lengths in the optimum range between about 5 inches and about 6 inches, the optimum angle is between about 3 degrees and about degrees. With shorter length tongue, angles in the range of between about 7 /2 degrees and about degrees may be used.

Referring to the drawings given by way of illustration of an embodiment of the invention and without intention to limit the invention thereto,

Figure 1 is an elevational view of a spout corner of the bag embodying the invention.

Figure 2 is a vertical sectional view through the filling spout.

2,855,136 Patented Oct. 7, 1958 Figure 3 is a perspective sectional view showing the valve in detail.

Figure 4 is a fragmentary view of the extension used in conjunction with a gusseted type bag.

Figure 5 is a fragmentary view of the extension used in conjunction with a plain corner bag.

Referring to the drawings, the numeral 10 refers to a bag which may be of any desired shape, but in the embodiment shown is rectangular and adapted with gussets along the lateral sides.

The bag is preferably formed of a heavy grade of kraft paper, and the right end may be made into a tube of irregular top edge configuration having one or more plies of paper for strength. The ends of bag 10 may be closed by any suitable means as, for example, by means of a U-shaped strip of web 12 secured as by stitching 13 to the ends of the bag.

An opening 14 is provided for filling purposes. This opening is formed by inverting or turning inwardly a corner 15 of the bag so as to form an insert at the corner integral with the bag which has the lower edge of the insert angled upwardly from the horizontal.

Corner 15 is produced as follows: A sheet of paper is originally cut as shown in Figure 4 with an extension 16. Extension 16 is positioned in such manner that the fold 1'7 substantially bisects the extension 16 into two portions 18 and 19. After formation of the sheet into a tube, extension 16, which is now at one edge of the tube, is inverted into the bag by folding in a manner such that the portions 18 and 19 fall back to back. As illustrated in Figure 3, the fold 17 in a gusseted type bag is folded inwardly and the folds 20 and 21 become the outer edges of the bag. With the gusset folded inwardly at a distance from the top of the extension 16 depending upon the length of spout desired, and preferably about 7 inches from the top in bags of about 30 inches length and designed to hold between about pounds and about pounds of solids, an approximately 1 inch portion 22 of fold 17 is made in a forward direction; and the balance of the corner plus extension 16 is folded inwardly so that the edges 23 and 24 of extension 16 form parallel straight edges which are also parallel to the top edge of the bag. When the bag is sewn as by stitching 13, a valve is formed which the force of solids can not force outward. This folding with about 5 /2 inches inverted tongue and about 1 inch forward fold will give about a 10 degree tip to the inwardly extending valve.

The invention has been illustrated with reference to a gusseted bag, but is applicable to nongusseted bags. With a change in the shape of extension 16, for example, to the form shown in Figure 5, the folding operation is very similar. The extension 31 of sheet 30 is formed with edges 32 and 33 parallel to the top edge of said blank, and edges 34 and 35 transverse to the horizontal. When extension 31 is inverted, edges 34 and 35 may be moved to horizontal position, the same as edges 23 and 24 of extension 16 described above. The bag may then be stitched closed with the valve of the nongusseted bag secured by a single horizontal stitching operation.

Having thus fully described and illustrated the character of the invention, what is desired to be secured and claimed by Letters Patent is:

A valve-type closure in a flat closed-end gusseted paper bag comprising an inwardly diagonally folded upper corner portion providing a trough-like filling passageway, said inwardly folded portion being integral with the bag, the bottom of the inwardly folded portion being defined by a crease, the inner end of said crease terminating at the inner open end of the folded portion and the outer end of the crease terminating in the gusset fold of the bag 3 adjacent the side edge of the bag, said crease extending inwardly and upwardly at an angle from the horizontal inthe range between about 3 and about 15".

References Cited in the file" of this patent' UNI-TED STATES 4 Litchfield Jan. 16, 1934 Rose Feb; 28; 1939'- Haungs Sept. 1, 1942 FOREIGN PATENTS Germany Aug. 13, 1931 Great Britain Oct. 15, 1931 Great Britain Nov. 9, 1936 

